[FPDI] Soken Shows Off Twist Ball Type E-paper Covering a Full Wall

Nov 4, 2008
Takuya Otani, Nikkei Electronics
E-paper covering the entire surface of a wall
E-paper covering the entire surface of a wall
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An e-paper clock
An e-paper clock
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A prototype driven by organic transistors
A prototype driven by organic transistors
[Click to enlarge image]

Soken Chemical & Engineering Co Ltd arranged its 30 x 30cm electronic papers vertically and horizontally on the entire surface of a wall standing in the company's booth.

The e-paper used is the so-called twist ball type. And it displays images by rotating fine particles whose upper and lower surfaces are painted in different colors.

Though the principle of the method has been known for some time, Soken is "probably the only company that is seriously trying to commercialize twist ball type e-paper," the company's staffer said. The company has technologies for the production of fine particle, etc, and applied them to its new e-paper.

The twist ball is made of acrylic resin and has a diameter of 0.1mm. Colors for the upper and lower surfaces can be selected from various combinations such as black and white, red and white, and green and black, according to Soken.

One of the colors is positively charged while the other is negatively charged. A sheet formed with an array of many balls is sandwiched by drive and transparent electrodes. The balls are rotated by the voltage applied to the electrodes.

The exhibited e-paper enables the bilevel display with two colors painted on the balls. In principle, images can be displayed in gradations by controlling the degree of rotation, Soken said.

Along with the e-paper covering the entire surface of the wall, the company prototyped a clock by using two 30 x 30cm e-papers side by side. They are driven by patterned electrodes.

In addition, Soken showed off a 4-inch e-paper display that represents dots using a combination of twist ball technology and organic transistors. It has a resolution of 60 x 120. The company did not reveal the manufacturer of the organic transistors.

FPD International 2008